معالجة النماذج في PHP

<form method="POST" action="process.php">
    <!-- Form fields go here -->
    <button type="submit">Submit</button>
</form>

<?php
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $name     = $_POST['name'] ?? '';
    $email    = $_POST['email'] ?? '';
    $password = $_POST['password'] ?? '';
    $bio      = $_POST['bio'] ?? '';
}
?>

<form method="POST" action="">
    <input type="text" name="name" placeholder="Username"><br>
    <input type="email" name="email" placeholder="Email"><br>
    <input type="password" name="password" placeholder="Password"><br>
    <textarea name="bio" placeholder="About yourself"></textarea><br>
    <button type="submit">Register</button>
</form>

<?php
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $gender = $_POST['gender'] ?? '';
    $skills = $_POST['skills'] ?? [];   // Checkboxes come as an array
    $city   = $_POST['city'] ?? '';

    echo "Gender: {$gender}<br>";
    echo "Skills: " . implode(', ', $skills) . "<br>";
    echo "City: {$city}<br>";
}
?>

<form method="POST" action="">
    <label>Gender:</label>
    <input type="radio" name="gender" value="male"> Male
    <input type="radio" name="gender" value="female"> Female
    <br>

    <label>Skills:</label>
    <input type="checkbox" name="skills[]" value="php"> PHP
    <input type="checkbox" name="skills[]" value="mysql"> MySQL
    <input type="checkbox" name="skills[]" value="js"> JavaScript
    <br>

    <label>City:</label>
    <select name="city">
        <option value="">Choose...</option>
        <option value="beijing">Beijing</option>
        <option value="shanghai">Shanghai</option>
    </select>
    <br>

    <button type="submit">Submit</button>
</form>

<?php
$errors = [];
$name = $email = '';

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $name  = trim($_POST['name'] ?? '');
    $email = trim($_POST['email'] ?? '');

    if ($name === '') {
        $errors[] = 'Username is required';
    }
    if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
        $errors[] = 'Invalid email format';
    }

    if (empty($errors)) {
        echo "<h3 style='color:green'>Registration successful! Welcome, {$name}!</h3>";
        $name = $email = '';  // Clear fields on success
    } else {
        echo "<ul style='color:red'>";
        foreach ($errors as $e) echo "<li>{$e}</li>";
        echo "</ul>";
    }
}
?>

<form method="POST" action="">
    <input type="text" name="name" placeholder="Username"
           value="<?= htmlspecialchars($name) ?>"><br>
    <input type="email" name="email" placeholder="Email"
           value="<?= htmlspecialchars($email) ?>"><br>
    <button type="submit">Register</button>
</form>

<?php
$gender = $_POST['gender'] ?? 'male';
$skills = $_POST['skills'] ?? [];
?>

<!-- Radio buttons: use the checked attribute -->
<input type="radio" name="gender" value="male"
       <?= $gender === 'male' ? 'checked' : '' ?>> Male

<!-- Checkboxes: check with in_array -->
<input type="checkbox" name="skills[]" value="php"
       <?= in_array('php', $skills) ? 'checked' : '' ?>> PHP

<!-- Dropdown: use the selected attribute -->
<select name="city">
    <option value="beijing" <?= $city === 'beijing' ? 'selected' : '' ?>>Beijing</option>
</select>

<?php
// Method 1: Check the request method (recommended)
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // Process the form
}

// Method 2: Check for the submit button
if (isset($_POST['submit'])) {
    // Process the form
}

// Method 3: Check if any POST data arrived
if (!empty($_POST)) {
    // Process the form
}
?>

<?php
// prg.php
session_start();

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // Process the data
    $name = trim($_POST['name'] ?? '');
    
    // Store a flash message in the session
    $_SESSION['flash_message'] = "Welcome, {$name}!";
    
    // Redirect to the same page with a GET request
    header("Location: " . $_SERVER['PHP_SELF']);
    exit;
}

// Display any flash message
if (isset($_SESSION['flash_message'])) {
    echo "<div style='color:green'>{$_SESSION['flash_message']}</div>";
    unset($_SESSION['flash_message']);
}
?>

<form method="POST" action="">
    <input type="text" name="name" placeholder="Username">
    <button type="submit">Register</button>
</form>